Refactored prepare_namelist, added import on __init__

  * Added a new task to coupled that calls prepare_namelist
    in mom4 and agcm.
  * Added coupled and agcm to import in __init__ so fabric
    task finding works again.
Refactored check_restart, moved to models
Pep8 and PyFlakes fixes
Refactored clean_experiment
Refactored check_status

  * Created check_status tasks for each model
  * Created new function print_ETA, estimated time calculation
    is independent of model (and it made check_status
    on each model simpler)
  * Avoided pokemon programming (gotta catch'em all!) while
    checking status, it was enough to check if RE searching
    returned anything.